Epidemiology and survival of systemic sclerosis-sarcoidosis overlap syndrome.

OBJECTIVE: We evaluated the epidemiology, manifestations, serology, comorbidities, and survival among systemic sclerosis (SSc) patients with and without sarcoidosis.

METHODS: We conducted a retrospective cohort study comparing SSc patients with and without sarcoidosis. All patients fulfilled the ACR-EULAR classification criteria for SSc. Sarcoidosis was based on physician diagnosis and/or confirmatory biopsy. The primary outcome was time from diagnosis to all-cause mortality. Survival was evaluated using Kaplan-Meier curves.

RESULTS: We included 1977 patients (1971 SSc, 6 SSc-sarcoidosis) with a SSc-sarcoidosis prevalence of 0.30%. Sarcoidosis frequently preceded SSc (66.66%). The most frequent sarcoidosis manifestations were pulmonary (66.66%), lymphadenopathy (66.66%), arthritis (50.00%), cutaneous (33.33%), and hepatic (16.66%). SSc and SSc-sarcoidosis patients had female:male sex ratios of 4.5:1 versus 5:1 and median ages of SSc onset of 48.3 versus 43.8 years. Interstitial lung disease (35.00% versus 66.66%) and pulmonary hypertension (24.91% versus 50.00%) tended to occur more frequently while abnormal nailfold capillaries (34.70% versus 16.66%) and digital ulcers (33.33% versus 16.66%) tended to occur less frequently among SSc-sarcoidosis patients, but the differences were not significant. There was an increased frequency of stroke among the SSc-sarcoidosis patients (relative risk 8.59 (95%CI 1.02-72.0)). The median survival times were 23.4 years for SSc-sarcoidosis and 18.6 years for SSc, with no differences in survival curves, log-rank test 0.55.

CONCLUSION: Sarcoidosis in SSc is rare but appears to occur more frequently than the general population. It is associated with pulmonary, lymph node, cutaneous, joint and hepatic involvement. Stroke occurs more frequently in SSc-sarcoidosis patients but with no differences in survival.